I love my Sorex 28's. I race in Holland, hence moderate temperatures. I just put them on my car, clean them with a bit of break cleaner and take off, leaving every one around wondering where the hell I get my grip from. :-) No grip potion smearing, no tyre heaters. Just put them on and enjoy the race.

Everyone at our club uses sorex 28 for night time racing.
This rubber is so good its not funny, the rubber just sticks to the ground.
I have used hpi x[aterns which are pretty good but the car does not go aournd the track anywhere near as fast..
I would receommend these to all racers out there, be sure to check track temperature,
I race in australia at night, this rubber is perfect.